Many other societies around the world have also valued plant-based natural products for their life-giving properties. For example, reserpine (1.4), which is used to control hypertension, was isolated from the roots of a shrub called Rauvolfia littolaris ex.
The purpose of isolation and characterisation of active natural products
The lack of information about active ingredients contained in different parts of medicinal plants is a major problem for users of natural products in their natural state. Therefore, the study of natural products from medicinal plants is of great importance in both developing and developed countries.
Aims of the project
Based on these many reasons, he undertook the project "Isolation and characterization of secondary metabolites of two Asteraceae species, Artemisia afra and Elytropappus rhinocerotis". Preparations from these two medicinal plants have been used by Africans for many years to treat many diseases.
The family Asteraceae
The genus Artemisia is one of the genera grouped under the tribe known as Anthemideae. Most of the genera are distributed in the northern hemisphere; in the southern hemisphere it has representatives in South Africa, Australia and South America1.
The genus Artemisia
- Description
- Phytochemistry of some Artemisia species
This species was found in Mongolia and was chemically investigated by Jakupovic et al.12, who isolated three types of compounds. As pointed out by Haouari and Ferchichi,20 it is a herbaceous, aromatic and medicinal plant.
Review of Artemisia afra Jacq. ex. Willd
- Historical background
- Description
- Uses
- Previous chemical investigation
The basal stems of the plant are thick, firm and woody compared to the upper parts of the plant. Moody et al.46 in their GC and GC-MS analysis of the essential oil of A.
Results and discussion
Introduction
This may be due to many factors, such as the age of the plant, the season in which the plant material was collected, the organ of the plant studied and mainly the geographical location of the wild plant. Given that hexane is a nonpolar solvent with zero polarity index, the resulting extract was expected to contain less polar extract components, and 2.56 and 2.57 were isolated.
Structural elucidation of taurin (2.56)
Evidence for the presence of an α-substituted methyl lactone in 2.56 is also derived from NMR data. The structure was confirmed by agreement between the NMR data 2.56 and the values published by Gonzalez et al.51 who isolated taurine from A.
Structural elucidation of artesin (2.57)
A comparison of the 13C NMR data of 2.56 and 2.57 showed that these two compounds were closely related. Therefore, it was concluded that the ketone group in taurine (2.56) was reduced to an alcohol.
Structural elucidation of maritimin (2.58)
In the HMBC experiment, 1H,13C correlations were observed between methyl protons resonating at δH 1.24 and the ketone carbon (δC 210.8), an aliphatic quaternary carbon (δC 49.2), a methylene carbon (δC 28.0), and one of the oxygen-containing quaternary carbons (δC 63.7). An α-epoxide and a β-epoxide will have the same NMR characteristics and, therefore, we were unable to confirm the configuration of the epoxide by this method.
Structural elucidation of artemin (2.59)
Artemin (2.59) can be formed by reduction of the C-1 carbonyl and the acid-catalyzed rearrangement of maritimin (2.58) (Scheme 2.1). Indirectly, the α-configuration of the 5-hydroxy group in artemin (2.59) confirmed the α-configuration assigned to the 4,5-epoxide in maritimin (2.58).
Structural elucidation of norsantolinifolide (2.61)
Scopoletin (7-hydroxy-6-methoxycoumarin) (2.66) was isolated from the CH2Cl2-MeOH crude extract of the aerial parts of A. Geographically, Gnaphalieae are distributed worldwide but are common in South Africa and Australia.1 The name Elytropappus is derived from Greek words "elytron" meaning "shell" and "pappos" meaning "fluff" or "fluff", referring to the small cup-like rim around the base of the feathery pappus.
Structural elucidation of santolinifolide (2.62)
Structural elucidation of reynosin (2.65)
A literature search revealed that 2.65 is the structure of Reynosin, a compound first isolated in 1970 by Yoshioka et al. Studies showed that Reynosin (2,65) has important biological activities, such as inhibition of CINC-1 induction in LPS-stimulated rat kidney epitheloid NRK-52E cells.64 It also showed inhibitory effect on the production of TNF -alpha in a dose-dependent manner .65.
Structural elucidation of scopoletin (2.66)
68 , 69 The compound also exhibited significant anti-inflammatory and antimicrobial activities when isolated by Yu et al. Panda and Kar reported its antithyroid and antihyperglycemic activity in hyperthyroid rats, after isolating 2.66 from Aegle marmelos.72 Other properties include immunomodulatory effects and hepatoprotective action, as shown by Manuele et al.
Structural elucidation of p-hydroxyacetophenone (2.67)
Structural elucidation of 2,4-dihydroxy-6-methoxyacetophenone
The 13C NMR spectrum (panel 65) showed nine peaks, four of which are quaternary carbons; one signal at δC 203.4 was assigned to the carbonyl carbon of the acyl group. Since no significant chemical shift difference was observed for the two meta-coupled aromatic protons, the 2,3,5-oxygenation pattern was also excluded and the structure of the compound was assigned as 2,6-dihydroxy-6-methoxyacetophenone (2,68) .
Structural elucidation of 5-hydroxy-7,4′-dimethoxyflavone (2.69)
This supported the idea of the existence of symmetry in the second aromatic ring of the isolated compound due to the methoxy group resonating at δC 55.5 and attached to C-4' (δC 162.6). The isolation of 5-hydroxy-7,4'- dimethoxyflavone or 7,4'-dimethyl ether of apigenin called 4'-O-methylgenkwanin (2.69) was previously reported by Nkunya et al.
Comparison of the thujone and ketone chemotypes of A. afra
The one with Rf 0.38 is present in the thujone type and almost absent in the ketone type. Scopoletin (7-hydroxy-6-methoxycoumarin) is present in higher concentration in thujone than in the ketone type chem.
Conclusion
Experimental procedures
- General methods
- Plant material
- Extraction
- Isolation of compounds
- Isolation of taurin (2.56)
- Isolation of artesin (2.57)
- Isolation of maritimin (2.58)
- Isolation of scopoletin (2.66)
- Isolation of p-hydroxyacetophenone (2.67)
- Isolation of norsantolinifolide (2.61)
- Isolation of 2, 4-dihydroxy-6-methoxyacetophenone (2.68)
- Isolation of santolinifolide (2.62)
- Isolation of artemin (2.59)
- Isolation of reynosin (2.65)
- Isolation of 5-hydroxy-7,4′-dimethoxyflavone (2.69)
Each time, 20 g of plant material was soaked in solvent, left overnight, and the yield of crude extract was determined. A portion of the hexane extract (10 g) was then dissolved in a small volume of hexane and filtered through a short silica gel column, eluting with hexane. The resulting fraction was spotted on a TLC plate using hexane-EtOAc (7:3) as a solvent system.
Maritimine (2.58) was obtained after repeated column chromatography of 10 g of the crude extract of the ketone chemotype. Seven grams of the crude CH2Cl2-MeOH fraction was subjected to column chromatography eluting with hexane-EtOAc (6:4).
Asteraceae) trichome-specific cDNA reveals CYP71AV1, a cytochrome P450 with a key role in the biosynthesis of the antimalarial lactone sesquiterpene artemisinin. Susceptibility of opportunistic bacteria and yeasts to the volatile oils of Artemisia afra, Lippia javanica, Lippia scaberrima, Myrothamnus. Sesquiterpene lactones from Artemisia genipi Weber: isolation and determination in plant material and liquors.
Inhibitory effect of sesquiterpene lactones from Saussurea lappa on tumor necrosis factor alpha production in murine macrophage-like cells. Evaluation of antithyroid, antioxidant and antihyperglycemic activity of scopoletin from Aegle mameros leaves in hyperthyroid rats.
Introduction
Studies show that it is used in the treatment of many conditions such as digestive disorders, hypertemia, acidity in children, stomach cancer and fever. 6 In case of lack of appetite it is taken as a tonic and the preparations are believed to stimulate sweating. In the Western Cape, people use it to treat diarrhea and convulsions in children and typhoid fever in both children and adults.7,8 Reports confirm that it was a famous drug during the 1918 influenza epidemic.7,8,9.
In addition to the four main components of the leaf resin, benzoic acid (3.6) and its derivatives, p-hydroxybenzoic acid (3.7), protocatechuic acid (3.8) and veratric acid (3.9), have been confirmed to be present in small amounts. , as well as cinnamic acid derivatives, namely p-coumaric acid (3.10), ferulic acid (3.11) and sinapic acid (3.12). The author of this thesis finds it difficult to believe that a polar compound like quercetin will be soluble in diethyl ether.
Results and discussion
- Preparation of plant material and isolation of compounds
- Structural elucidation of labdanolic acid (3.13)
- Structural elucidation of methyl labdanolate (3.14)
- Structural elucidation of scoparone (6,7-dimethoxycoumarin) (3.15)
- Structural elucidation of viridiflorol (3.16)
These results, together with COZY (plate 82) and HSQC (plate 83) spectra, confirmed the structure of the isolated compound to be labdanoic acid (3.13). The determination of the structure of methyl labdanolate (3.14) was easy, as it is similar to that of labdanoic acid. The spectroscopic data for the isolated compound were in good agreement with the reported data for methyl labdanoate (3.14).
The analysis of the spectroscopic data of the isolated compound led to the assignment of the structure of the compound as viridiflorol or (1S,4R,5S,6R,7R tetramethyltricycloundecan-10α-ol (3.16). The experimental data were in accordance with the reported data from Bombarda et al.24 for viridiflorol (3.16) isolated from Melaleuca quinquenervia.
Conclusion
It has been found that when viridiflorol (3.16) is applied to dog food bait, it effectively reduces the consumption and visitation of fire ants. At a concentration of 18 µg/mg dog food, fire ants will not consume the bait within six hours of application of viridiflorol. This suggests that this compound may act as an antifeedant for some insects. Viridiflorol (3.16) has also been reported to occur in other different species, including Kunzea ambigua, a therapeutic and insect repellent species,27 Mentha piperita L.,28 and in different chemotypes of Melaleuca quiquenervia,29 a species known to be aggressive towards other species, 30,31 but have antiseptics with bioactivity against human pathogens.32.
Experimental procedures
- General experimental procedure
- Plant material and extraction
- Isolation of labdanolic acid (3.13)
- Isolation of scoparone (6,7-dimethoxycoumarin) (3.15)
- Isolation of methyl labdanolate (3.14)
- Isolation of viridiflorol (3.16)
Twelve fractions of 15 ml each were collected, concentrated in a fume chamber, applied to TLC plates and visualized by UV radiation. These fractions were combined and the solvent evaporated by rotavapor to give 10 mg of white needle crystals, Rf = 0.45 (hexane-EtOAc, 6:4). In order to isolate this compound, it was necessary to separate the acidic and non-acidic components of the crude extract.
A saturated solution of sodium bicarbonate (10 mL) was added and the two layers were gently mixed. The above process in Section 3.4.5 was repeated and the non-acidic material from the crude extract was chromatographed using isocratic elution with hexane-CH2Cl2 (15:5).
Effect of scoparone (6,7-dimethoxycoumarin) biosynthesis on the resistance of Tangelo nova, Citrus paradis and Citrus aurantium fruits to Phytophtora parasitica. Preventive effect of 6,7-dimethoxy-coumarin for rats subjected to single-y irradiation of the whole body. abstract available on Scifinder Scholar). Dietary influences on terpenoids sequestered by biological control agent oxyops vitiosa: effect of plant volatiles from different Melaleuca quinquenervia chemotypes and laboratory host species.
Isolation and characterization of these compounds were mentioned in the goals three and four of the project, so they were achieved. The known inhibitory action of labdanolic acid on the COX-2 enzyme may explain the ethnobotanical use of the plant as an anti-inflammatory agent.
The isolated and characterized compounds include an acid, labdanolic acid; an ester, methyl labdanolate; a coumarin, scoparone or 6,7-dimethoxycoumarin; and a sesquiterpene alcohol, viridiflorol or (1S,4R,5S,6R,7R tetramethyltricyclo-undecan-10α-ol.
